1. Field of the Invention
The present invention relates to a method for shaping an essentially flat-surfaced blank to form a shell body and the use thereof.
2. Background of the Related Art
Methods of this nature to manufacture shell bodies from essentially flat-surfaced blanks, round plates or similar sheet-metal panels are generally known. EP 1 728 567 B1, for example, relates to a method and a pertinent device for shaping an essentially flat-surfaced blank in form of a round and/or discoidal sheet-metal element to form a shell body with distinct reduction of its wall thickness. In this process, a rotating, flat-surfaced, circular blank, for example a pre-shaped round plate, is attached to a ring or clamping plate along its circumference, is flared with a roll into an open space behind the ring or clamping plate and, as appropriate, is shaped to forma rotation-symmetric shell body with end-shaped dimensions. Depending upon the degree of required concavity, this is usually done in several separate steps, whereby the round-plate material is plastically extended and is azimuthally stretched owing to surface expansion in the membrane section. This method and the pertinent device have already absolutely proven their worth in practical application. In the process of shaping of shell bodies with small wall-thickness/diameter ratios, creases might form in the sheet metal. In order to reduce the formation of creases, which in addition depends upon the E-module of the material to be shaped at the selected shaping temperature, and the amount of subsequent mechanical post-processing work, additional devices are recommended, which according to U.S. Pat. No. 3,355,920 are designed to enable calibration of the shape.